Reversible hydrogen adsorption on Co/N4 cluster embedded in graphene: The role of charge manipulation

- H2 adsorption on the neutral and positively charged Co/N4/G cluster.
- The adsorption energy of H2 molecule on Co/N4/G can be dramatically enhanced by injecting positive charges on the adsorbent.
- H2 adsorption/release occurs spontaneously without any energy barriers once charges are removed.

Electrical charging of Co/N4 cluster embedded in graphene (Co/N4/G) is proposed as an approach for electrocatalytically switchable hydrogen adsorption. Using density functional theory, we found that the H2 molecule is weakly adsorbed on the uncharged Co/N4/G cluster. Our results show that the adsorption energy of hydrogen molecule on Co/N4/G cluster is significantly increased by introducing extra positive charges into the cluster. Once the charges are removed, H2 molecule spontaneously desorb from the Co/N4/G absorbent. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the Co/N4/G nanomaterial is excellent absorbent for controllable and reversible adsorption and release of H2.

The Adsorption Energy of H2 Molecule on Co/N4/G Can be Dramatically Enhanced by Injecting Positive Charges on the Adsorbent.65